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PubMedDate not supplied

Osteogenesis imperfecta congenita and tarda: a temporal bone report.

The temporal bone report of an operated case of osteogenesis imperfecta tarda is presented. Histological examination confirmed the presence of bilateral fixation of the footplate by otosclerosis as the cause of the conductive hearing loss. Fragility of bony septae in the mastoid and of the stapedial crura were observed. Sensorineural impairment in later years with a reduction in neural elements in the cochlea appear related to the extent and activity of the otosclerotic foci. Additional temporal bone reports of three cases of osteogenesis imperfecta congenita show lack of deposition of the skein-like bone in the endochondral layer, sparse bony septae in marrow spaces and deficiency of the perosteal layer. The stapedial crura were thin and in two cases both were deformed and fractured.

Aged↗
PubMedDate not supplied

Osteogenesis imperfecta of the temporal bone and its relation to otosclerosis.

Osteogenesis imperfecta (OI) designates a heterogeneous group of heritable disorders of connective tissue that in addition to bone may affect tendons, ligaments, fascia, skin, sclerae, blood vessels, teeth, and hearing. The current classification identifies at least four major syndrome groups or types. It also recognizes a considerable number of additional syndromes that may represent supplementary types or subgroups. Loss of hearing is the least constant of the prominent features of OI. Its incidence varies between 26% and 60%. In OI, formation and remodelling of bone are variously affected. In the temporal bone the development of the inner ear capsule may be involved severely. In the stapes the disturbance in lamellar bone formation can lead to extreme thinness, dehiscence, and nonunion of the stapedial superstructure with the footplate. Osteogenesis imperfecta can be associated with otosclerosis, another bone dysplasia with a different morphology. Otosclerosis, in turn, may interfere with sound conduction and perception. Thus, the hearing loss encountered in OI may be the result of OI, otosclerosis, or a combination of both.

Adolescent↗
PubMed1991

Stapes surgery in osteogenesis imperfecta: analysis of postoperative hearing loss.

The disappointing results in 12 of 58 stapedectomies, including 4 revision operations, performed on osteogenesis imperfecta patients were analyzed and compared with reports in the literature. It is concluded that the results described as disappointing were not always the product of the stapes operation. A progressive sensorineural hearing loss arising independently of the operation as a result of progression in the disease process of osteogenesis imperfecta appears to have a severe influence on the final hearing threshold.

Adolescent↗
PubMed1992

Osteogenesis in marrow-derived mesenchymal cell porous ceramic composites transplanted subcutaneously: effect of fibronectin and laminin on cell retention and rate of osteogenic expression.

Cultured-expanded rat marrow-derived mesenchymal cells differentiate into osteoblasts when combined with a porous calcium phosphate delivery vehicle and subsequently implanted in vivo. In this study, the effects of ceramic pretreatment with the cell-binding proteins fibronectin and laminin on the osteogenic expression of marrow-derived mesenchymal cells were assessed by scanning electron microscopy, [3H]-thymidine-labeled cell quantitation, and histological evaluation of bone formation. Scanning electron microscopic observations showed that marrow-derived mesenchymal cells rapidly spread and attach to both fibronectin- or laminin-adsorbed ceramic surfaces but retain a rounded morphology on untreated ceramic surfaces. Quantitation of [3H]-thymidine labeled cells demonstrated that laminin and fibronectin preadsorbed ceramics retain approximately double the number of marrow-derived mesenchymal cells than do untreated ceramics harvested 1 wk postimplantation. Histological observations indicate that the amount of time required to first detect osteogenesis was shortened significantly by pretreatment of the ceramic with either fibronectin or laminin. Fibronectin- and laminin-coated ceramic composite samples were observed to contain bone within 2 wk postimplantation, while in untreated ceramic the earliest observation of bone was at 4 wk postimplantation. A comparison was made of the initial cell-loading, in vivo cell retention characteristics, and rate of osteogenesis initiation of marrow-derived mesenchymal cells on two types of ceramic with different pore structure and chemical composition, with and without preadsorption with fibronectin or laminin. "Biphasic" ceramics contain randomly distributed pores 200-400 microns in diameter, and "coral-based" ceramics have continuous pores of approximately 200 microns in diameter. Laminin or fibronectin preadsorption significantly increases the number of cells retained in all ceramic test groups by day 7 postimplantation. In addition, by day 7 postimplantation, the biphasic ceramics retain a significantly greater number of cells for all test groups than do coral-based ceramics. The biphasic ceramics consistently have more specimens positive for bone with the identical cell-loading conditions used throughout this study. These results indicate that the retention of cells within the ceramic is an important factor for optimization of marrow mesenchymal cell initiated bone formation. The retention of cells within ceramics is augmented by the adsorption of the cell-binding proteins laminin and fibronectin, but this effect varies depending on ceramic pore structure and/or chemical composition.

Animals↗
PubMed2000

Skewfoot in patients with osteogenesis imperfecta.

We report skewfoot deformities in two patients who have osteogenesis imperfecta. A discussion will follow proposing etiologies of skewfoot, speculating that the ligamentous laxity often present in children who have osteogenesis imperfecta may predispose the development of skewfoot.

Adolescent↗
PubMed2003

Fourth brachymetatarsia treated with distraction osteogenesis.

BACKGROUND: This study investigated metatarsal lengthening by distraction osteogenesis for fourth brachymetatarsia in 22 metatarsals (16 patients). METHODS: From May 1997 to May 2000, lengthening was performed with a monoexternal fixator, and distraction was started at a rate of 0.5 mm per day after a latency period of approximately 7-10 days. RESULTS: The average gain in length was 16.5 mm (range, 13-21 mm), equivalent to an increase of 39% (range, 28-51%), and the average healing index was 72.9 days/cm (range, 51.7-95.7 days/cm). The American Orthopaedic Foot and Ankle Society (AOFAS) average score for lesser toe was 86.3 (range, 47-100). The most common residual complication was subluxation of metatarsophalangeal (MTP) joint in five cases, with partial or total stiffness of the MTP joint. These complications happened in the group of metatarsals excessively lengthened more than 40% and made the AOFAS score poorer. The other complications were three cases of angular deformity in the lengthened bone, and two cases of pin-tract infection. CONCLUSION: Although distraction osteogenesis is an effective method to address fourth brachymetatarsia, stiffness or subluxation of the MTP joint was not uncommon. To avoid complications that can happen as a result of excessive lengthening, careful preoperative radiographic measurement to calculate the optimal amount of lengthening may help us to avoid overlengthening and the complications that accompany it.

Adolescent↗
PubMed2005

The adaptive remodeling of condylar cartilage---a transition from chondrogenesis to osteogenesis.

Mandibular condylar cartilage is categorized as articular cartilage but markedly distinguishes itself in many biological aspects, such as its embryonic origin, ontogenetic development, post-natal growth mode, and histological structures. The most marked uniqueness of condylar cartilage lies in its capability of adaptive remodeling in response to external stimuli during or after natural growth. The adaptation of condylar cartilage to mandibular forward positioning constitutes the fundamental rationale for orthodontic functional therapy, which partially contributes to the correction of jaw discrepancies by achieving mandibular growth modification. The adaptive remodeling of condylar cartilage proceeds with the biomolecular pathway initiating from chondrogenesis and finalizing with osteogenesis. During condylar adaptation, chondrogenesis is activated when the external stimuli, e.g., condylar repositioning, generate the differentiation of mesenchymal cells in the articular layer of cartilage into chondrocytes, which proliferate and then progressively mature into hypertrophic cells. The expression of regulatory growth factors, which govern and control phenotypic conversions of chondrocytes during chondrogenesis, increases during adaptive remodeling to enhance the transition from chondrogenesis into osteogenesis, a process in which hypertrophic chondrocytes and matrices degrade and are replaced by bone. The transition is also sustained by increased neovascularization, which brings in osteoblasts that finally result in new bone formation beneath the degraded cartilage.

Adaptation, Physiological↗
PubMed2005

Osteoclastogenic activity during mandibular distraction osteogenesis.

Mandibular distraction osteogenesis is a well-developed clinical modality for the treatment of craniofacial deformities and dental arch discrepancies, in combination with orthodontic treatment. However, in our previous study, orthodontic tooth movement into the distraction gap caused severe root resorption. The present study aimed to clarify the osteoclastogenic activity of cells in the distraction gap. We hypothesized that the gene expression of osteoclastogenic- and osteoclast-supporting molecules in osteoblasts and stromal cells would increase at distraction sites during the consolidation period. An animal model experiment involving rabbits was designed for mandibular distraction osteogenesis and subjected to in situ hybridization analysis. The number of osteoclasts was larger in the distraction gap during the early consolidation period than in normal controls, due to an increase of gene expression for osteoclastogenic cytokines in osteoblasts. It was concluded that osteoclastogenic and osteoclastic activities are stimulated at distraction sites during the early consolidation period.

Animals↗
PubMed2005

Single-dose pharmacokinetics and tolerability of alendronate 35- and 70-milligram tablets in children and adolescents with osteogenesis imperfecta type I.

CONTEXT: Alendronate (ALN) is a bisphosphonate compound that can be administered orally and has potential use in pediatric osteoporotic conditions. OBJECTIVE: The objective was to evaluate the pharmacokinetics and single-dose tolerability of ALN in children with osteogenesis imperfecta. DESIGN: ALN was administered iv and orally in a two-period, randomized crossover study, with doses separated by a 2-wk washout and follow-up carried out within 2 wk after the last ALN dose. SETTING: The study was conducted at the pediatric metabolic bone research unit at the Shriners Hospital for Children, Montréal, Canada. PATIENTS: Twenty-four children (aged 4-16 yr; eight girls) with osteogenesis imperfecta type I participated. INTERVENTIONS: All patients received iv ALN at a dose of 125 mug. In addition, patients weighing less than 40 kg received an oral dose of ALN 35 mg, whereas those weighing 40 kg or more received ALN 70 mg orally. MAIN OUTCOME MEASURES: Total urinary excretion and oral bioavailability of ALN, blood and urine safety parameters, and adverse events were the main outcome measures. RESULTS: The total urinary excretion of ALN after the iv dose was similar for both weight groups. The mean oral bioavailability (95% confidence interval) was 0.43% (0.28, 0.64%) for patients weighing less than 40 kg and 0.56% (0.36, 0.87%) for patients weighing 40 kg or more. Eighteen patients reported a total of 44 clinical adverse experiences, none of which were serious. The most common adverse experiences were mild to moderate headache (n = 7), nausea (n = 7), fever (n = 5), and abdominal pain (n = 6). Eighty percent of the adverse experiences (35 of 44) occurred within 48 h of medication administration, 91% (40 of 44) lasted less than 24 h, and 84% (37 of 44) were reported after oral dosing. Laboratory safety monitoring revealed a marginal decrease in absolute lymphocyte count and serum alkaline phosphatase after the study compared with baseline for both weight categories. CONCLUSIONS: The mean oral bioavailability of 35- and 70-mg ALN tablets was less than 0.6%, comparable to adult studies. Adverse experiences from single-dose ALN were minor, and the drug was generally well-tolerated.

Adolescent↗
PubMed1988

Infantile chronic subdural hematoma with local protrusion of the skull in a case of osteogenesis imperfecta.

Osteogenesis imperfecta with infantile chronic subdural hematoma is extremely rare and has not been previously described in the literature. Our patient was a baby girl suffering from osteogenesis imperfecta tarda (Type I) who had an acute subdural hematoma at birth and who developed a progressive chronic subdural hematoma with local protrusion of the overlying skull. She was treated surgically with a good result. This rare complication is due to weakness of an insufficiently calcified skull, which is peculiar to this disorder of bone and connective tissue development.

Chronic Disease↗
PubMed2006

Glucocorticoid-induced osteogenesis is negatively regulated by Runx2/Cbfa1 serine phosphorylation.

Glucocorticoid hormones have complex stimulatory and inhibitory effects on skeletal metabolism. Endogenous glucocorticoid signaling is required for normal bone formation in vivo, and synthetic glucocorticoids, such as dexamethasone, promote osteoblastic differentiation in several in vitro model systems. The mechanism by which these hormones induce osteogenesis remains poorly understood. We demonstrate here that the coordinate action of dexamethasone and the osteogenic transcription factor Runx2/Cbfa1 synergistically induces osteocalcin and bone sialoprotein gene expression, alkaline phosphatase activity, and biological mineral deposition in primary dermal fibroblasts. Dexamethasone decreased Runx2 phosphoserine levels, particularly on Ser125, in parallel with the upregulation of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1) through a glucocorticoid-receptor-mediated mechanism. Inhibition of MKP-1 abrogated the dexamethasone-induced decrease in Runx2 serine phosphorylation, suggesting that glucocorticoids modulate Runx2 phosphorylation via MKP-1. Mutation of Ser125 to glutamic acid, mimicking constitutive phosphorylation, inhibited Runx2-mediated osteoblastic differentiation, which was not rescued by dexamethasone treatment. Conversely, mutation of Ser125 to glycine, mimicking constitutive dephosphorylation, markedly increased osteoblastic differentiation, which was enhanced by, but did not require, additional dexamethasone supplementation. Collectively, these results demonstrate that dexamethasone induces osteogenesis, at least in part, by modulating the phosphorylation state of a negative-regulatory serine residue (Ser125) on Runx2. This work identifies a novel mechanism for glucocorticoid-induced osteogenic differentiation and provides insights into the role of Runx2 phosphorylation during skeletal development.

Amino Acid Substitution↗
PubMed1989

The role of expanding intramedullary rods in osteogenesis imperfecta.

We report the results of using 83 expanding intramedullary rods in 24 children with osteogenesis imperfecta after a mean follow-up of five years three months. In all, 62% of the rods have expanded after one primary operation. Thirty-four additional operations were necessary; 11 for the correction of rotation or angulation deformities and 23 for revision of the rod or T-piece. All these revisions were successful. Complications were more frequent in children who required very small rods. Problems with Bailey-Dubow rods led to the development of the Sheffield rod system; 17 bones treated with these rods are included in the series. Before surgery only eight of the 24 children were able to walk but at review 20 children were walking, 15 without walking aids. Elongating intramedullary rods should be available to all children with osteogenesis imperfecta as they improve walking capability, reduce the number of fractures, prevent deformity and allow integration of the child into society.

Adolescent↗
PubMed2000

Low-intensity pulsed ultrasound accelerates bone maturation in distraction osteogenesis in rabbits.

We investigated the effects of low-intensity pulsed ultrasound on distraction osteogenesis in a rabbit model. Callotasis of the right tibia was performed in 70 male Japanese white rabbits using mini-external fixators. In the first part of the study in 64 animals using normal distraction (waiting period seven days; distraction rate 0.5 mm/12 hours; distraction period ten days), we evaluated the distraction site by radiography, measurement of the bone mineral density (BMD), mechanical testing, and histology. In the second part in six rabbits using fast distraction (waiting period 0 days; distraction rate 1.5 mm/12 hours; distraction period seven days) the site was evaluated radiologically. Half of the animals (35) had received ultrasound to their right leg (30 mW/cm2) for 20 minutes daily after ceasing distraction (ultrasound group), while rigid fixation only was maintained in the other half (control group). With normal distraction, the hard callus area, as shown by radiography, the BMD, and the findings on mechanical testing, were significantly greater in those receiving ultrasound than in the control group. Histological analysis showed no tissue damage attributable to exposure to ultrasound. With fast distraction, immature bone regeneration was observed radiologically in the control group, while bone maturation was achieved in the ultrasound group. We conclude that ultrasound can accelerate bone maturation in distraction osteogenesis in rabbits, even in states of poor callotasis.

Animals↗
PubMed2006

Fractures of the acetabulum in osteogenesis imperfecta.

We describe two patients aged 16 and 25 years with osteogenesis imperfecta who sustained displaced fractures of the acetabulum following minor trauma. The femoral heads were deformed by impact against the acetabular margin and both cases underwent surgical reconstruction. The quality of the bone and soft tissues made the operations challenging. There were potential complications specific to osteogenesis imperfecta, including bleeding, the creation of secondary fracture lines and shredding of the soft-tissue. The cases provide useful guidelines for addressing these difficulties.

Acetabulum↗
PubMed2004

Brittle IV mouse model for osteogenesis imperfecta IV demonstrates postpubertal adaptations to improve whole bone strength.

UNLABELLED: The Brtl mouse model for type IV osteogenesis imperfecta improves its whole bone strength and stiffness between 2 and 6 months of age. This adaptation is accomplished without a corresponding improvement in geometric resistance to bending, suggesting an improvement in matrix material properties. INTRODUCTION: The Brittle IV (Brtl) mouse was developed as a knock-in model for osteogenesis imperfecta (OI) type IV. A Gly349Cys substitution was introduced into one col1a1 allele, resulting in a phenotype representative of the disease. In this study, we investigate the effect of the Brtl mutation on whole bone architecture, strength, and composition across a range of age groups. MATERIALS AND METHODS: One-, 2-, 6-, and 12-month-old Brtl and wildtype (WT) mice were analyzed. Femurs were assessed at the central diaphysis for cortical geometric parameters using microCT and were subsequently mechanically tested to failure by four-point bending. Matrix material properties were predicted using microCT data to normalize data from mechanical tests. Raman spectroscopy and DXA were used to assess matrix composition. RESULTS: Our findings show a postpubertal adaptation in which Brtl femoral strength and stiffness increase through a mechanism independent of changes in whole bone geometry. These findings suggest an improvement in the material properties of the bone matrix itself, rather than improvements in whole bone geometry, as seen in previous mouse models of OI. Raman spectroscopic results suggest these findings may be caused by changes in mineral/matrix balance rather than improvements in mineral crystallinity. CONCLUSIONS: Our findings parallel the currently unexplained clinical observation of decreased fractures in human OI patients after puberty. The Brtl mouse remains an important tool for investigating therapeutic interventions for OI.

Adaptation, Physiological↗
PubMed2005

Cyclical intravenous pamidronate treatment affects metaphyseal modeling in growing patients with osteogenesis imperfecta.

UNLABELLED: This analysis of 50 growing patients with osteogenesis imperfecta revealed that 2-4 years of pamidronate treatment lead to abnormalities in the shape of the distal femoral metaphyses. INTRODUCTION: Cyclical intravenous pamidronate therapy is of clinical benefit in children and adolescents with moderate to severe osteogenesis imperfecta (OI) but might interfere with the shaping of long bone metaphyses during growth. MATERIALS AND METHODS: We evaluated the distal femur in 50 growing children with moderate to severe OI (mean age, 6.7 +/- 3.4 years; 26 girls) who had received 2-4 years of pamidronate therapy (annual dose, 9 mg/kg body weight). The mediolateral width of the distal femoral growth plate and of the metaphysis, as well as the ratio between these two measures (called metaphyseal index), were determined on lower limb radiographs. RESULTS: Compared with untreated OI patients who were matched for OI type and age, pamidronate-treated patients had similar growth plate width but wider metaphyses, resulting in a 26% higher metaphyseal index (p < 0.001). Apart from the effect on bone shape, each pamidronate cycle induces a transverse line in metaphyses that are adjacent to active growth plates. Analyses of these transverse lines revealed that they persist for an average time of approximately 4 years, with a range from 2 to 8 years. CONCLUSIONS: Pamidronate interferes with the process of periosteal resorption that is normally responsible for shaping the distal femoral metaphysis. Pamidronate-induced transverse lines disappear with time, supporting the view that these lines represent horizontal trabeculae that undergo remodeling. There is no evidence at present that these treatment induced morphological changes have any clinical implications.

Bone Density Conservation Agents↗
PubMed1998

Histomorphometry of distraction osteogenesis in a caprine tibial lengthening model.

Standardized histomorphometry of bone formation and remodeling during distraction osteogenesis (DO) has not been well characterized. Increasing the rhythm or number of incremental lengthenings performed per day is reported to enhance bone formation during limb lengthening. In 17 skeletally immature goats, unilateral tibial lengthenings to 20 or 30% of original length were performed at a rate of 0.75 mm/day and rhythms of 1, 4, or 720 times per day using standard Ilizarov external fixation and an autodistractor system. Two additional animals underwent frame application and osteotomy without lengthening and served as osteotomy healing controls. Histomorphometric indices were measured at predetermined regions from undecalcified tibial specimens. Within the distraction region, bone formation and remodeling activity were location dependent. Intramembranous bone formed linearly oriented columns of interconnecting trabecular plates of woven and lamellar type bone. Total new bone volume and bone formation indices were significantly increased within the distraction and osteotomy callus regions (Tb.BV/TV, 226% [p < 0.05]; BFR/BS, 235-650% [p < 0.01]) respectively, compared with control metaphyseal bone. Bone formation indices were greatest adjacent to the mineralization zones at the center of the distraction gap; mineral apposition rate 96% (p < 0.01); mineralized bone surfaces 277% [p < 0.001]); osteoblast surfaces 359% [p < 0.001]); and bone formation rate (650% [p < 0.01]). There was no significant difference (p < 0.14; R = 0.4) in the bone formation rate of the distracted callus compared with the osteotomy control callus. Within the original cortices of the lengthened tibiae, bone remodeling indices were significantly increased compared with osteotomy controls; activation frequency (200% [p < 0.05]); osteoclast surfaces (295% [p < 0.01]); erosion period (75%); porosity (240% [p < 0.001]). Neither the rhythm of distraction nor the percent lengthening appeared to significantly influence any morphometric parameter evaluated. Distraction osteogenesis shares many features of normal fracture gap healing. The enhanced bone formation and remodeling appeared to result more from increased recruitment and activation of bone forming and resorbing cells rather than from an increased level of individual cellular activity.

Animals↗
PubMed2000

Osteogenesis from cultured chick periostea has a specific requirement for chloride.

Bone development, like embryonic development in general, depends on a particular internal electrical milieu. Ions are the carriers of currents that maintain this internal environment. In embryonic bone, chloride is a major carrier of such current. To explore the role chloride plays in embryonic bone development we performed several ion-removal experiments, using the chick periosteal osteogenesis (CPO) system as our model. We found that if chloride is reduced in the medium and replaced with a nontoxic anion, alkaline phosphatase (ALP) activity does not rise, nor does osteogenic development occur. However, acid phosphatase (AP) activity is not affected by level of chloride. Experiments using metabolic inhibitors showed that explants cultured in low chloride medium remain viable. Dose-response studies revealed that the response of ALP activity to chloride concentration is sigmoidal, with a [Cl-]0.5 of 45.9 mM. Reciprocal transfers of explants between complete and low chloride medium show that the rise in ALP activity depends on the length of time explants are cultured with chloride. In contrast, such transfer experiments show that osteogenesis requires chloride only during days 2-3 of culture.

Acid Phosphatase↗